Silver halide photographic sensitized paper producing black or blue black image

ABSTRACT

A SILVER HALIDE PHOTOGRAPHIC SENSITIZED PAPER PRODUCING BLACK OR BLUE BLACK IMAGE TONE AFTER DEVELOPMENT AND WHICH IS ENDURABLE AGAINST HOT-GLAZING, CAN BE OBTAINED BY ADDING A SELECTED COMBINATION OF THE TWO SORTS OF BLUEBLACK TONERS (DESIGNATED AS COMPOUNDS A AND B) IN THE EMULSION LAYER OR IN LAYERS ADJACENT THERETO. COMPOUNDS A COMPRISE SOME DERIVATIVES OF N-ALKYL-BENZOXAZOLINE-2THIONES, N-ALKYL-BENZOTHIAZOLINE-2-THIONES, N,N&#39;&#39;-DIALKYLBENZIMIDAZOLINE-2-THIONES AND N-ALKYL-1,2-DIHYDRO-QUINOLINE-2-THIONES, AND COMPOUNDS B COMPRISES 3-ALKYL, ARYL OR ARALKYL DERIVATIVES OF 4-ACYLAMIDO - 1,2,4 - TRIAZOLINE-5THIONES.

United States Patent Olhce 3,666,471 Patented May 30, 1972 3,666,471 SILVER HALIDE PHOTOGRAPHIC SENSITIZED PAPER PRODUCING BLACK R BLUE BLACK lMA E Yasushi Ohyama, Takatsuki-shi, and Kiyoshi lhltaki, Senji Tosa, Yoshikazu Horiuchi, and Akira Takemura, Kyoto, Japan, assignors to Mitsubishi Paper Mills, Ltd., Tokyo, Japan No Drawing. Filed Oct. 29, 1969, Ser. No. 872,376 Claims priority, application Japan, Nov. 1, 1968, 43/ 79,276 Int. Cl. G03c 1/86, 5/46, 7/00 US. CI. 9685 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a silver halide photographic sensitized paper useful for the production of photographic prints with excellent blue black to pure black image tone and density which is endurable against hot-glazing. And more particularly it relates to moderate to high speed enlarging papers which are stable and not liable to produce fog.

A known process of manufacturing photographic paper which produces a blue-black image after development is to employ a chloride rich emulsion and add to it some of the blue-black toners of the type which comprises heterocyclic compounds containing only nitrogen as the hetero atom, such as quinoline, quinine, benzotriazole or S-nitrobenzimidazole. They are usually very effective for silverchloride or chloride rich emulsions but not effective for silver bromide or bromide rich emulsions. Therefore the above mentioned combination is usually inferior in speed and the prints made from them are liable to change color to purplish dark brown or rosy black, to show a reduction in density and to decrease their contrast after hot-glazing or drying at elevated temperature. This phenomenon has been well known as bronzing in the art.

And it is also well known that the bronzing is prevented by certain heterocyclic substances containing a mercapto group, such as mercapto-benzothiazole or mercaptobenzimidazole, both also well known as anti-foggants. And it is true that no reduction in density is shown after hotdrying of the prints in the case when some of these mercaptans are introduced in the emulsion and sometimes even a slight increase in density is observed. But difiiculties are often recognized in maintaining the beautiful blue-black tone of the prints and color change of the prints to brown black or violet-black occurs very often. And among these mercapto compounds known as anti-bronzing agents, there is also another type of powerful compounds, which shows blue-black toning efiect together with anti bronzing property, such as l-phenyl-S-mercapto-l,2,3, 4-tetrazole, which is also well known as a powerful anti-foggant for yellow fog. This type of compound, however, shows the serious defect of impairing the optical sensitization of silver halide emulsions, due to its extraordinary strong adsorption on the silver halide grain surface.

The inventors did intensive research on the abovementioned problems to find out the ideal blue-black toner which is effective in bromide rich emulsions and in itself has an anti-bronzing property and does not show any desensitizing and fogging effect on the emulsion at the same time, and finally found out that it is very diflicult to obtain single compounds which have the above-mentioned balanced excellent properties in themselves, and that these balanced effects are achieved only by the combined use of two or more different compounds.

There are also many combinations of known blue-black toners or anti-foggants, e.g. the numerous aforementioned compounds or the famous tetrazaindene derivatives, and also triazolo-thiadiazole compounds of some of the inventors, and the inventors finally found out that the object is achieved by the application of the following two types of blue-black toners in combination, one type of substances having somewhat of a rather sensitizing eifect due to their development accelerating property and the other substances having scarcely any desensitizing effect in spite of their extraordinarily strong anti-fogging property, and both are strong anti-bronzing blue-black toners.

The selected combination of these two types of blueblack toners is as follows; namely a selected combination of one or more species of the two types of substances, one type being compounds having the following general Formula A,

(where X is a member selected from the group consisting of 'O"', r I|\I and -CH=CH-, R and R are lower alkyl groups and R" is a member selected from the group consisting of hydrogen (non-substituted), halogen, methoxy, ethoxy and lower alkyl groups) and the other type being compounds having the general Formula B IIH (B) (where each of IR1 and R is selected from the group consisting of lower alkyl, aryl and aral-kyl groups).

The compounds having the general Formula A can be classified depending upon the kind of X as follows;

(1) N-alkyl-benzoxazolidine-Z-thiones and their R" derivatives,

(2) N-alkyl-benzothiazoline-Z-thiones and their R" derivatives, 1

(3) N,N'-dialkyl-benzimidazoline-2-thiones and their R" derivatives, i'

(4) N-alkyl-l,Z-dihydro-quinoline-2-thiones and their R" derivatives,

and the compounds having the general Formula B can be 7 called as 3-alkyl, aryl or aralkyl derivatives of 4-acyl-f amido-1,2,4-triazoline-2-thiones.

The methods of preparation of almost all compounds" having general Formula A have been known in the literature; but no process was known as to (3) N,N'-dialkylbenzimidazoline-Z-thiones before one of the inventors reported in detail on Yakugaku Zasshi 74 (1954), pp.

1365-1369, in which preparative methods for compounds #A-7 and #A-8 are disclosed as follows:

1-rnethyl-2-methylthiobenzimidazole methiodide (I) 6.4 g. of 1-methyl-2-rnethylthiobenzimidazole and 5.4 g. of methyl iodide was heated in a sealed tube at 80 C. for 20 hours and then the obtained crystals were recrystallized in methanol. The melting point was 145 to 147 C. The yield was 7.3 g. G T-1 N 18, calculated value I 39.6, determined value I 39.25.

1,3-dirnethyl-Z-benzimidazolinethione (#A-7) (i) 0.5 g. of (I) was weakly heated and refluxed for one hour in 1 cc. of pyridine, then the pyridine was removed under reduced pressure and the residue was washed with water. The recrystallization was made in methanol. The melting point was 151 to 152 C. The yield was quantitative. (ii) (I) was suspended in a two-fold amount of benzene and heat-refluxed for 48 hours to obtain (#A-7). (iii) 1.3g. of N,N'-dimethyl-O-phenylenediamine and 5 cc. of CS 'were heated and refluxed in a water bath for 6 hours and then anexcess of CS was removed. The residue was recrystallized in methanol. The melting point was 151 to 152 C. The crystals as obtained in (i), (ii) and (iii) and having the melting point of 151 to 152 C. were fused together with one another but there was found no drop in the melting point.

1,3 -diethyl-Z-benzimidazolinethione (#A-8) 2.3 g. of l-ethyl-2-ethylthiobenzimidazole and 1.8 g. of ethyl iodide were heated in a sealed tube at 100 C. for 48 hours and the approximately same amount of pyridine was added thereto. The mixture was weakly heated and refluxed for one hour and pyridine was removed. 5% HCl was added thereto and the extraction effected with 50 cc. of ether. The ether layer was twice washed with 20 cc. of a 1% NaOH solution. The drying was effected with anhydrous sodium sulfate and the distillation effected. The boiling point was 185 C. The recrystallization in methanol achieved colorless columnar crystals having a melting point of 39.5 to 41 C. The preparative methods of the compounds having general Formula B are already mentioned by some of the inventors in another patent application. A brief explanation of the method is, therefore given below. These compounds are synthesized by reacting 4- amino-1,2,4triazoline-5-thione, which in itself is a condensation product of thiocarbohydrazide and a carboxylic acid, and then with an acid chloride or an acid anhydride of a carboxylic acid, as described below;

For example, 72 g. of 4-amino-3-ethyl-1,2,4-triazoline-5- thione obtained by heating 106 g. of thiocarbohydrazide with 222 g. of propionic acid at 140-150" C. for 9 hours (yield 86 g. 60%, melting point 149-150 C.) is added to 100 ml. of acetic anhydride and the mixture is heated at 90-95 C. for 3.5 hours. After cooling, the separated crystals are dissolved in an aqueous solution of sodium hydroxide and then the pH thereof is adjusted to 5 with hydrochloric acid to produce 4-acetamido-3-ethyl-1,2,4- triazoline-S-thione (yield 35 g., melting point 202-203" (2.). Similarly, other derivatives can be easily obtained.

Both series of compounds include a considerable num- '4 ber of species and some of the readily obtainable most eifective species specified are as follows;

The compounds having the general Formula A:

Compound A4:

/0 3-eghyl-6-me1tihyl enzoxazo ne- CH thione.

Compound A-2:

Compound A3:

3-propyl-benzoxazoline-Z-thione.

Compound A-fi:

Compound A45:

CzHs 1,3-diethyl-benzimiq idazoline-2thlone.

Compound A4):

t CH3 Compound A-IO:

benzimidazoline- Z-thione.

Lethyl-lfi-dihydroqumoline-2thione.

1-propyl-6-ehloro-1,2-

dihydroquinoline- 2-thione.

The compounds having the general Formula B:

Compound B-3:

Compound B-5:

Compound B-7:

N-NH

3-ethyl4-aoetamido- 1,2,4-triazoline-5- thione.

3-methyl-4-propionamide-1,2,4- triazoline-fi-thione.

3-propyl-4- propionamido- 1,2,4-triazo1ine-5- thione.

3-butyl-4-aoetamido- 1,2,4-triazoline-5- thione.

3-phenyl-4-proplonamido-1,2,4- triazoline-dthione.

3-pheny1-4- benzamido-1,2,4- triazoline-o-thione.

3-ethyl4- phenylaoetamido- 1,2,4-triazoline-5- thione.

Compound 13-8:

NH-C 0-CzH 3-pontyl-4-propionamide-1, /N\ triazoline-b-thione; C5Hn-fi (|J=S N-NH Compound B-9:

NH-C O-CzHs 3-heptyl-4-propion- I amido- /N\ triaZ01ine-5-thione. C H --C C=S NNH The purpose of this invention is attained by adding one or more species of blue-black toners having the general Formula A and one or more species of those having the general Formula B to a silver halide emulsion, especially chloro-bromide emulsion after digestion, :but before application on a support. In this case, other known additives may also be used if necessary and furthermore, some of the additives may be separately added to an over layer (protective layer), under layer or intermediate layer other than the emulsion layer to cause them to diffuse during development. Since the additives of this invention have no serious desensitizing effect on the emulsion, it is not always necessary to separate them from the emulsion layer, but in some cases, they are preferably added separately as mentioned above.

Generally speaking the total amount of the two types of compounds used in combination according to the invention is in the range of 0.1-5.0 g. per kg. of silver content of the emulsion calculated as AgNO and the amount varies depending upon the kinds of emulsion (grain size and crystal structure of silver halide, composition of halides, etc.), recipe of emulsion, kinds and amounts of gelatin used, manner and degree of sensitization or kinds and amount of other anti-foggants and emulsion stabilizers added. So the optimum amount must 'be determined by experiment in each case.

And the suitable effective additives which can be used in combination with the above-mentioned compounds of our invention are as follows; l-phenyl-S-mercapto-l,2,3,4- tetrazole, S-chlorobenzo-triazole, diphenyl iodonium iodide, sodium salt of benzene sulfinate or some derivatives of 4-hydroxy-1,3,3a,7-tetrazaindene and triazolethiadiazole mentioned before.

The invention will be illustrated in the following examples.

EXAMPLE 1 2.0 g. of Compound #A-8 and 1.2 g. of Compound #B-4 were dissolved in ethanol and the resultant solution was added to high speed chloro-bromide emulsion (which contained about mol percent of silver bromide) obtained from 1 kg. of silver nitrate immediately before application together with the other pre-application additives. Thereafter, the thus obtained mixture was applied to a baryta-paper in such a manner that the amount of silver was about 2.5 g./m. calculated as AgNO and lphenyl-S-mercapto-1,2,3,4-tetrazole was added to a protective over-layer which was applied on said layer in an amount such as to provide 0.001 g./m. of the tetrazole after being dried.

A cyanine sensitizing dyestuff having sensitizing maximum at the wavelength below 520 me was added to said emulsion to enhance the speed of the paper. The two kinds of additives of this invention did not inhibit the color sensitization and thus a high speed photographic paper for enlargement having excellent preservability can be easily produced. The color tone of the prints after development using conventional methods was a beautiful blue-black tone near pure black and a high temperature glazing treatment caused no change of color tone or reduction of density.

7 EXAMPLE 2 In the same manner as in Example 1, 1.5 g. of Compound #A-Z, 1.0 g. of Compound #B-1 and 0.4 g. of S-n-actyl-6-methyl-4-hydroxy-1,3,3a,7-tetrazaindene were added to chloro-bromide emulsion (which contains about 60 mol percent of silver bromide) obtained from 1 kg. of silver nitrate and coating of the emulsion layer was barytaged photographic base paper was followed by the application of a protective over-coating which contained 0.001 g. of compound #A- and 0.001 g. of l-phenyl-S- mercapto-1,2,3,4-tetrazole per square meter.

A moderate speed enlarging paper vn'th excellent blueblack tone and rapid developing characteristics, using conventional methods, was obtained.

EXAMPLE 3 2.5 ml. of a 1% solution of a Compound #A-4, 3.0 m1. of 1% solution of Compound #B-6 and 1.0 ml. of a 1% solution of Z-mercaptobenzothiazole were added to a gaslight emulsion (mainly composed of silver chloride containing a small amount of both bromide and iodide) obtained from 100 g. of silver nitrate. The emulsion was applied on a baryta-paper followed 'by the application of a conventional protective over layer upon it to obtain a gaslight paper which was developed using conventional methods to produce a beautiful blue-black tone and the prints showed no bronzing by hot-glazing.

What is claimed is:

1. A silver halide sensitized photographic paper adapted to produce a black or blue-black image upon exposure and suitable development, said sensitized paper comprising a paper base layer having a silver halide emulsion layer coated thereon, said sensitized paper including at least one coating layer containing a combination of blue-black toners comprising at least one compound having the general Formula (A) where X is a member selected from the group consisting of -O, S,

8 and --CH=C H-, R and R are lower alkyl groups and R'f is a member selected from the group consistingof hydrogen, halogen, methoxy, ethoxy and lower alkyl groups and at least one compound having the general Formula 3 5. photographic paper as in claim 1 wherein X is 6. A photographic paper as in claim 1 wherein X is 7. A photographic paper as in claim 4 wherein R is C ll- R" is hydrogen, R is C H and R is CH 8. A photographic paper as in claim 5 wherein R is C H R" is hydrogen and R and R are phenyl.

9. A photographic paper as in claim 6 wherein R and R are C l-I R" is hydrogen, R is CH and R is CH References Cited UNITED STATES PATENTS 2,590,775 3/1952 Kendall et al. 96 96 X 2,668,113 2/1954 Schwalenstocker 9696 3,020,155 2/1962; Yackel a a1 9696 X ROBERT F. BURNETT, Primary Examiner W. E. HOAG, Assistant Examiner US. Cl. X.R. 96-52 

